And post '72s have to longer springs, too. When there was no choice but the stiff lifts I found that hydraulic shocks were the way to go vs gas. I don't run high speeds over washboard so caviation from heat is not a concern. Gas resists bottoming better and that is a non-issue with that type of spring. A weaker/softer shock made a big difference. All you need shocks for n a truck with stiff springs is to control bounce. You WANT all the compression you can get with those.
I wanted to put springs on my '72 so bad for so long, and money is what was keeping me, I finally said screw it and got the Suspension Special just so I could mount my aluminum slots with 35" BFG before they were toast. They were toast
and one blew in a few hundred miles. That, and I went with add-a-leafs/2" blocks I had and tossed the 4" blocks. The 2" blocks ended up being crappy, so I bought new ones. The rounded corner u-bolts (nuts down) I didn't like so ordered Ruff Stuff Nuts up bolts and plates. All this ended up bringing the cost closer to what the EZ-Ride kit cost. If I knew all that before I never would have gone that route (my kind of luck). Now I am back to wanting at least to change the fronts to EZ-Rides.